Water Level Monitor

By T.J. Byers
Published on May 1, 1980
1 / 3

PHOTO 1: The sensor tube you'll be submerging in your tank. PHOTO 2: Ten 220 k-ohm resistors wired in parallel. PHOTO 3: The back of the meter, wired in parallel with a zenner diode.   PHOTO 4: The meter in its wall-mounted wood base.
PHOTO 1: The sensor tube you'll be submerging in your tank. PHOTO 2: Ten 220 k-ohm resistors wired in parallel. PHOTO 3: The back of the meter, wired in parallel with a zenner diode.   PHOTO 4: The meter in its wall-mounted wood base.
2 / 3

Wiring schematic and wall mount diagram for the meter.
Wiring schematic and wall mount diagram for the meter.
3 / 3

Photo and wiring schematic show how to add transistors and additional resistors to your water watcher to increase its sensitivity.
Photo and wiring schematic show how to add transistors and additional resistors to your water watcher to increase its sensitivity.

The amount of water that’s held in storage at my remote homestead is of critical interest to me since I’m well out of reach of the nearest public utility. But I also have far more to do in a day than play nursemaid to a cistern. So, at the height of last year’s dry season, when my water worries were at their worst, I put together a remote water level monitor for my tank.

Based on a few common electronic components, my device has proven to be infallible over the last 14 months. And now, monitoring the level in my holding tank — which used to involve a wearying and time-wasting walk up the hill — is as easy as glancing at my living room wall.

Water Conducts

Don’t be intimidated because a few electronic gizmos go into the construction of my device. The components are easy to install, and the water sensor itself is simply based on the fact that water does a better job of conducting electricity than does air. If you place evenly spaced electrodes inside of the tank, wire them in parallel, and then apply current at the container’s bottom, the amount of current returned to the meter will be in proportion to the number of electrodes that are in contact with the conducting liquid.

The Sensor Tube

You can begin building your own water monitor by assembling the sensor tube, which consists of a piece of 1″ Schedule 40 PVC pipe (three inches longer than the depth of the tank’s maximum water level) and eleven No. 10 stainless steel, self-tapping sheet metal screws. The fasteners function as electrodes, and you can determine the proper position for each one by dividing your cistern’s maximum water depth into ten equal segments. (For example, if the water is 30 inches deep, there should be a mark every three inches.)

Comments (0) Join others in the discussion!
    Online Store Logo
    Need Help? Call 1-800-234-3368